Cache memories are used in various data storage applications. For example, some disk drives use a hybrid configuration in which a Non-Volatile Memory (NVM—e.g., Flash memory) is used as cache memory for a Hard disk Drive (HDD). Hong and Shin, for example, describe such hybrid configurations, in “NAND Flash-based Disk Cache Using SLC/MLC Combined Flash Memory,” 2010 International Workshop on Storage Network Architecture and Parallel I/Os, May, 2010, which is incorporated herein by reference.